1. Field of the Invention
The present invention relates generally to reclosable packages and, more particularly, to a method of applying sliders to reclosable plastic bags using a duplex packing machine. The invention also relates to a duplex form, fill and seal packaging machine and to a slider applicator for a duplex packaging machine.
2. Description of the Related Art
Reclosable packages, such as, for example, slider-activated reclosable plastic bags, generally include a folded web, or pouch, and a zipper profile which receives a moveable slider used to open and reclose the pouch. When used to package goods, such as, for example, food items packaged for commercial sale, such packages often further include a removable header portion used to provide an additional, tamper evident seal of the pouch. Such header portion is located above the zipper profile and slider at the top of the package. Typically, the header portion is torn off or otherwise removed and discarded, in order to access the slider and thus open the pouch.
Such packages are usually mass produced using a packaging machine which performs forming, filling, sealing and cutting, or separating, operations sequentially, typically in a horizontal fashion. It is desirable to produce the packaged goods as quickly and efficiently as possible. Therefore, packaging machines commonly referred to in the art as duplex machines, have been developed. A duplex machine gets its name from the fact that it provides for the forming, filling, sealing and subsequent separation of two packages at a time, as opposed to requiring each package to be completed individually, before preparation of the next package is initiated. Duplex machines are, therefore, advantageous in that they are essentially twice as fast.
However, while duplex machines can typically employ two hoppers for simultaneously filling the packages, double sealing jaws for sealing the edges of two packages, and two cutters for subsequently simultaneously separating two finished packages, known duplex machines cannot employ two slider applicators. The application of sliders to the packages, in order to create a reclosable zipper has, therefore, not yet been adapted to be sufficiently compatible with the duplex running condition. The difficulty arises in that the zipper profile after being threaded through a first applicator in order to receive a slider, cannot, with the slider attached, pass through a second applicator in order to receive the second slider. Hence, the series of packages must be intermittently stopped in order to apply the sliders one at a time, thereby defeating the two at a time speed advantages of the duplex running condition.
There is a need, therefore, for an improved, more efficient packaging system and method which enables the application of sliders two at a time in order to be compatible with a duplex form, fill and seal machine and thereby increase production output.